I have a Lenovo W520 with 2nd gen i7, 8GB RAM, running Windows 7 64 bit, and foobar2000. The audio skips during network activity when using the Conexant audio driver, but it doesn't have this problem with the Microsoft High Definition Device driver. This is even when the buffer in foobar2000 is set to 1500 ms.

The problem with the Microsoft driver, is the volume is limited (maybe 5 dB lower) than the Conexant driver. This is unacceptable when driving the Sennheiser HD 600 headphones with ReplayGain enabled, especially during quite passages. Is it possible to bump up the volume of the system when using the Microsoft driver?

There, see if you have a tab labeled "personalized" or something like that. In that tab I have a checkbox named "Limited output". You need to uncheck this.

The tabs I have are General, Levels, Enhancements, and Advanced, and unfortunately there's not a limited output option. I have driver version 6.1.7601.17514 from 11/19/2010.

I have decided to send my laptop back to Lenovo, since it really should have worked out of the box, or at least with the latest drivers. I'll post again with my results. Thanks for all of the suggestions.